Electrode structure



Feb. 11, 1941. c, M m/E 2,231,330

ELECTRODE STRUCTURE Filed April 1. 1939 2 Sheets-Shat 1 c. M. GOVE 2,231,330

ELECTRODE STRUCTURE 7 Filed April 1, 1939 2 Sheets-Sheet 2 Patented Feb. 11, 1941 PATENT OFFICE nnncrnons STRUCTURE Charles M. Gove, Bound Brook, N. 1., asslgnor to Research Corporation, New York, N. Y., a corporation of New York Application April 1, 1939, Serial No. 265,531

14 Clalms. (Cl. 183-.-'i)

Thisinvention relates to the-electrical treatment of fluids and is particularly directed to improvements in discharge electrode structures for Cottrell electrical precipltators.

A principal purpose oi-the invention is the pro vision of-discharge electrode structures whereby the corona discharge may be controlled.

A further purpose of the invention is the provision of means for balancing and controlling the corona discharge from all portions oi a discharge electrode structure to produce maximum precipitating efiect upon suspended particles.

Another purpose of the invention is the provision of an electrode structure which will provide a maximum oi. corona discharge'with a relatively low voltage.

- Still another purpose of the'invention is the provision of an electrode structure the discharge characteristics oi which may be readily altered to suit varying operating conditions independent- 1y of changes. in the voltage or other characteristics onthe potential supplied thereto.

Other objects and advantages of the invention will be apparent from the following discussion.

Eiectrodestructures providing a high corona discharge at relatively low voltages by the use of very fine wires or sharp points having small radii of curvature'are known in the art. However, the known structures suffer from a number of disadvantages. The voltage at which corona discharge appears tends to decrease with decreasing radius of curvature of the electrode structure,

but when using finewires or points the decreasing stiffness of thel wi res or points requires the use of supporting members, which introduce'disadvantageous complications due in part to the shielding eflect of such members on the corona emitting portions and in part to the disturbing eilect of extended surfaces of low radiusof cur- I vature on the field distribution.

These disadvantages are avoided in the present invention'by the provision of electrode structures including sup orting members of relatively largeradius of curvature and corona discharge velements of relatively small radius of curvature, supported by said supporting members adjacent to but spaced from substanti: lly all the extended surfaces of the supporting members, for example, by helically disposed helices of fine-wire about the supporting members. r

The distance the corona discharging element extends out from the supporting-shrines may be varied within limits to regulate-the amount of corona discharge. when this, distance is less than inch the reduction in coronacurrent flow is very substantial, while when the distance is greater than inch the change in corona ,current flowwith changes in the distance is relatively small.

In general, it is desirable that the corona form- 5 ing elements should have a radius of curvature not exceeding about 0.5 millimeter or 0.02 inch and that they should project at least minimeters from the extended surface of the supporting member.

A particularly advantageous structure is provided by loosely coiling a flexible, but preferably non-resilient, helical coil of wire about a still! self-supporting conductive member. The discharge properties of this structure may readily be controlled by suitably selecting the diameter of the wire of which the coil is made and the pitch and diameter of the coil.

The invention will be described in further detail for the purpose of illustration with reference to the accompanying drawings in which:

Fig. l is a sectional elevation 01' a vertical flow electrical precipitator embodying the principles oi the invention;

Fig. 2 is an elevationv in partial section taken at right angle to the view of Fig. 1;

Fig. 3 is an enlarged detail of a discharge electrode structure of the invention; and

Fig. 4 is an elevation in partial section of a pipe precipitator embodying the invention.

In Figs. 1 and 2, i0 is the shell oia precipitate ing chamber having inlet, or outlet, I I and outlet, or inlet, i2, and provided with spray devices 2! in theupper portion. The chamber is provided witha plurality of, parallel plate collecting electrodes it supported from and in electrical com tact with the grounded shell ill. Between the collecting electrodes ii are provided a plurality of discharge electrode structures comprising fr'amemembers l4, ll. .Upper frame member 40 Mi is supported upon beams i5 carried by insucharge electrode structure are wire coilszll providing discharge elements.

The relation of the membersill to the supporting elements ll, H is shown more clearly in Fig. 3. .From this figure it may be seen that the outer portions of the members 20 provide a series of discharge points or attenuated elements 20' spaced from the support a distance governed by the diameter of the coil and spaced from each other a distance governed by the pitch of the coil. The coils are attached to the support at convenient points, for example, by welding, The wire is preferably non-resilient, so that the coils tend to retain their positions on the supports in spite on portions of the discharge electrode system,

' are eliminated.

The precipitator of Fig. 4 consists of a shell 40 having spray devices 4| in the upper portion thereof and provided with inlet 42 and outlet 43. Passing through and supported by horizontal partition 44 are a plurality of vertical pipes 45 which are in electrical connection with the grounded shell 40 and form collecting electrodes.

Axially supported in each of the collecting electrode pipes is a discharge electrode structure comprising a still supporting member 46 and an attenuated discharge member 41 providing elements of small radius of curvature spaced from the surface of the supporting member. The discharge electrode structure is ad vantageously formed 01' a coil of wire helically wound about the supporting member, as shown in detail in Fig. 3.

The supporting members 46 of the discharge electrode are carried by beams 48 which are suspended in horizontal position in the lower part of the precipltator from insulators 49 th ough one of which the electrodes are connected to a high potential source, not shown, by conductor 50. Passage of liquid along the beams into. the insulator chambers 5| is prevented by pipe sections 52 mounted on the beams and sloping toward the interior of the precipitator.

The discharge-electrode structure of this precipitator combines simplicity and economy of production on the one hand with ready adaptability to a wide range of operating conditions on the other and permits thedischarge characteristics of an electrical precipitator to be varied over a wide range at a negligible cost. A considerable variation can be obtained by merely altering the pitch at which the wire coil is wound about the supporting member, and much more said supporting member with the axis of the member and being in tangential contact with said supporting member at a plurality of points spaced along a helical path on the surface 01' the supporting member.

3. A discharge electrode structure comprising an electrically conductive supporting member of relatively large radius of curvature and a flexible corona discharge forming member supported thereby comprising a wire coil in contact with said supporting member, with the axis of the coil helically disposed about said supporting member the diameter of said 0011 being sufflcient to space the outermost portions of the convolutions thereof a sufiiclent distance from the surface of the supporting member to substantially eliminate the shielding effect thereof.

4. A discharge electrode structure comprising an electrically conductive supporting member of relatively large radius of curvature and a flexible corona discharge forming member supported thereby comprising a wire coil in contact with said supporting member with the axis of the coil helically disposed about said supporting member, the diameter of said coil being at least 1*; inch.

5. A discharge electrode structure comprising an electrically conductive supporting member of relatively large radius of curvature and a flexible corona discharge forming member supported thereby comprising a wire coil in contact with said supporting memberiwith the axis of the coil helically disposed about said supporting member, the wire of said coil having a radius not exceeding about 0.02 inch.

6. A discharge electrode structure comprising an electrically conductive supporting member of relatively large radius oi curvature and a flexible corona discharge forming member supported thereby comprising a wire coil .in contact with said supporting member with the axis of the 'coil helically disposed about said supporting member, the wire of said coil having a radius not exceeding about 0.02 inch and the diameter 01' said coil being at least inch.

'7. A discharge electrode structure comprising an electrically conductive supporting member of relatively large'radius of curvature and a flexible corona discharge forming member supported thereby comprising a coil of non-resilient wire in contact with said supporting member with the axis 01' the coil helically disposed about said supporting member.

8. In an electrical precipitator for the removal of suspended particles from gases, 8. collecting electrode and a discharge electrode structure comprising a plurality of extended surface supporting members, a plurality of corona discharge i'orming elements supported in spaced relation to said collecting electrode by said supporting members, and a plurality of corona discharge i'orming elements distributed over the extended surface oi said supporting members, said last named elements having a radius of curvature not exceeding 0.02 inch and extending from said supporting surface member -at least 1 inch and not more than inch.

9. In an electrical precipitator' for the removal f suspended particles from gases, 9. collecting electrode and a discharge electrode structure comprising a plurality of extended surface suplecting electrode and a discharge electrode structure comprising a plurality of extended surface supporting members, a plurality of corona discharge forming elements supportedin spaced relation to said collecting electrode by said supporting members, and a plurality of corona discharge forming elements distributed over the extended surface of said supporting members, said last named elements being provided by a coil of wire inv contact with. said supporting member with the axis of the coil helicallydisposed about said "supporting member. the diameter of said coil being at leastinch.

11. In an electrical precipitator for there-- moval of suspended particles from gases, a collecting electrode and a discharge electrode structure comprising a plurality of extended surface supporting members, a plurality of corona discharge forming elements supported in spaced relation to said collecting electrode by said supporting fnembers, and a' plurality of corona discharge forming elements distributed over the extended surface of said supporting members, said last named elements being provided by a coil or wire in contact with said supporting member with the axis of the coil helically disposed about said supporting member, the wire of said coil having a radius not exceeding about 0.02 inch.

12. In an electrical precipitator for the removal of suspended particles from gases, a collecting electrode and a discharge electrode structure comprising a plurality of extended surface s pporting members, a plurality of corona discharge forming elements supported in spaced relation to said collecting electrode by said supporting members, and a plurality of corona dis-, charge forming elements distributed over the extended surface of said supporting members,

. said last named elements being provided by a coil of wire in contact with said supporting member with the axis of the coil helically disposed about said supporting member, the wire of said coil having a radius not exceeding about 0.02

inch and the diameter of said coil being'at least 1% inch.

13. In an electrical precipitator for the removal of suspended particles from gases, a collecting electrode structure and a discharge electrode structure spaced from and electrically insulated from said collecting electrode structure and enveloped thereby on at least two sides, the discharge electrode structure comprising an extended surface supporting member, a plurality 0f corona discharge forming elements distributed over the surface of said member and a plurality of corona discharge forming elements depending from said member, said corona discharge forming elements being positioned and shaped to produce when energized substantially uniform precipitating effect from all portions of the dis charge electrode structure to the surfaces of the collecting electrode structure. a

14. In an electrical precipitator for the removal of .suspended particles from gases, a collecting electrode structure and a discharge electrode structure spaced from and electrically insulated from said collecting electrode structure and enveloped thereby on at least two sides, the discharge electrode structure comprising an extended, surface supporting member, a plurality of corona discharge forming elements distributed over thesurface of said member and a plurality of corona discharge forming elements depending from said member, the corona discharge forming elements distributed over the surface of said extended surface supporting member being spaced and shaped to provide when energized a precipitating effect from said inember to the collecting electrode structure substantially equivalent to the precipitating effect' from said depending corona discharge forming, elements to said collecting electrode 

